In the initialisation phase, the initiator uses the initialisation function from [1]} to initialise the global model and sends it to all clients. Let \(M_j \in \mathbb {R}^d\)  be the parameters of the model in the \(j\) -th iteration, where \(\mathbb {R}\)  is the set of real numbers, and \(d\)  is the number of model parameters. With \(Init: \varnothing \rightarrow \mathbb {R}^d\)  the initialisation function, the initialisation phase is then defines as
\(M_0 \leftarrow Init(\cdot ), M_0 \in \mathbb {R}^d .\) 
